Development of dual-fiber separation-based fiber-optic chemical sensors and their applications

Separation-based Fiber-optic Chemical Sensors (SBFOSs) are developed which integrate the highly efficient and fast separation technique known as capillary electrophoresis with the sensitive detection capabilities of fiber-optic-based laser-induced fluorescence (LIF) sensing. By employing the capillary electrophoretic separation technique, an extremely versatile element of selectivity is integrated with fiber-optic technology. This is advantageous because a single SBFOS potentially could monitor multiple analytes of interest in remote environments. Moreover, trace level monitoring of these multiple analytes is also possible with this sensor due to the sensitivity of LIF detection. Prototype SBFOS designs were based on a single-fiber approach, a single buffer reservoir, and a linear configuration. The focus of most of the work pursued herein was to overcome many of the operational and analytical drawbacks of the prototype sensors, and develop SBFOS designs that resulted in improved performance. To develop improved SBFOSs, the fundamental characteristics of fiber-optic detection and sampling considerations were explored. A dual-fiber SBFOS design was specifically pursued in this work to improve upon solute detection as well as to simplify the associated sensor optics. Efforts were also pursued to integrate automated injection devices to the SBFOSs for zonal mode of operation. Finally, potential applications, which have implications in either industrial process monitoring or in situ environmental monitoring, were developed.